Deflecting catheters, also referred to as steerable catheters are used in a variety of medical and non-medical procedures. In diagnostic and therapeutic medical procedures, a steerable catheter provides an operator (e.g., physician) with the ability to articulate the distal tip of the catheter in order to travel through constrained and/or tortuous anatomy, and/or to direct the distal catheter tip in a particular direction. Similar mechanisms are used in medical and nonmedical endoscopes to steer them to a target site and to orient a device portion (e.g., including a camera or other visualization means) in a desired direction.
In a typical design, control wires are manipulably attached at a proximal end of the device, and also attached at or near a distal end of the device. Such a configuration operates by manipulating one or more of the control wires to increase and/or decrease a generally longitudinal force on the distal device end that will deflect it in a desired direction. As described with reference to an existing steerable endoscopic camera device 50 of FIG. 1, the control wires may be actuated by rotation of control wheels 51, 53. Each control wheel can be rotated to operate a control wire or pair of control wires in a manner exerting push/pull tension on a deflectable distal device portion (not shown, but well-known in the art) to deflect that portion along a first plane, while the other control wheel operates similarly to deflect that portion along a second plane intersecting (e.g., orthogonal to) the first plane. At times, it is desirable to lock that distal device portion into a particular deflected orientation (e.g., so that the operator may execute another task requiring releasing hand contact with one or both control wheels). The illustrated device 50 includes a first brake for the first control wheel 51, with a twistable knob 55 for locking/unlocking an internal brake mechanism that operates along the central rotational axis of the first control wheel 51. The illustrated device 50 includes a second brake for the second control wheel 53, with a lever 57 for locking/unlocking an internal brake mechanism that operates by exerting a braking engagement along the central rotational axis of the second control wheel 53. One or both brake controls 55, 57 require a user to change his/her grip for actuation.
A variety of different steerable shaft constructions have been used in different prior catheters and endoscopes. Each shaft typically has at least one working channel that extends longitudinally therethrough (e.g., through a working channel port 58 in the handle, shown capped). A steerable catheter device may be configured as a gastrointestinal duodenoscope with a distal terminal end construction 59a as shown in FIG. 1A or as an endoscopic ultrasound (EUS) endoscope with a distal terminal end construction 59b as shown in FIG. 1B, which also shows a tool structure extending out through that scope's working channel lumen.
A variety of different steerable shaft constructions have been used in different prior catheters and endoscopes. However, there are special challenges and needs for a small-diameter catheter (e.g., less than 10 mm, less than 5 mm, or less than 4 mm and greater than 2.5 mm) configured for use through a side-viewing endoscope—such as a duodenoscope. In particular, such a device will need different resistance to crimping, kinking, and/or collapse along its length during operation and manipulation—including during introduction into and operation within a biliary tree of a human or non-human patient.
It is be desirable to provide a catheter shaft design that is configured and dimensioned for operation as a cholangioscope. Moreover, there is a need for a catheter device like this that provides economic diagnostic, therapeutic, and economic benefit to patients and caregivers by providing reliably predictable operative functionality and resistance to impaired structure or function during typical operations.